Speedometer problems

[Balber]

Hi all. Can you help me? When I drive alone, the speedometer needle lies down and does not show the speed. When I'm driving with a passenger, the speedometer shows the speed. On bumps the needle jumps down and up. Speed sensors are ok. No losses were found in the wiring. That is, the problem is partially solved when two people travel. Forza 300 2017.